WASHINGTON -- Scientists said on Thursday they had completed the first gene map of an animal -- a little roundworm that has been a mine of research information for years.
The worm, called Caenorhabditis elegans, is only about as big as the head of a pin. It lives in the dirt and eats even more lowly bacteria, the ubiquitous E. coli. But it has long been a favorite of researchers studying animal biology.
After nine years of work, joint teams working in the United States and Britain have mapped the worm's entire genome -- all its genes and other genetic material that controls those genes.
Despite its small size, C. elegans has more than 19,000 genes, and at least 40 percent of them match genes found in other animals, the researchers said.
"We have before us all the pieces of the puzzle that it takes to make a worm," Robert Waterston of Washington University in St. Louis, who led the US contribution to the effort, told a news conference.
"Now we need to figure out how it works," he added wryly.
"This is a watershed event in the history of biology," Dr. Harold Varmus, director of the National Institutes of Health, which helped fund the project along with Britain's Medical Research Council, said. "It is the first complete blueprint of a complex organism."
And although worms are very different from people, studying the genes of C. elegans will help scientists understand human beings.
"What's in a worm is in a person and we can use worms to analyze human genes -- where they are, how they work, and how they go wrong," said Robert Horvitz, a worm and human genetics expert at the Massachusetts Institute of Technology.
Teams around the world are examining the genomes -- the complete collection of genetic information including the genes -- of a variety of creatures, from bacteria to people.
The smaller the creature, the easier it is to sequence its genes. So far, only one-celled creatures such as viruses, yeast, and several bacteria have been sequenced.
C. elegans, which is found in huge numbers in the soil in temperate regions, is the biggest creature to be completed. It can cast enormous light on human genetics, the researchers said, acting as a kind of Rosetta stone to help decode the information held in DNA.
Although it is tiny, the threadlike nematode has much in common with more complex species, said Waterston.
"It's got muscles. It reacts to touch," he said. "It faces the same challenges other animals do." Genes involved in cancer, immune diseases, even AIDS, are found in C. elegans.
"The genes that it takes to make a nerve cell are very well represented in C. elegans," Waterston said. "The same is true for muscle."
Of all the human genes mapped so far, nearly two-thirds have an equivalent in the worm, which, in evolutionary terms, split off from the branch leading to humans about 600 million years ago.
"Seventy-four percent of (the known) human genes have worm counterpart," Horvitz said.
The presenilin genes involved in Alzheimer's disease also exist in the worm. "The only way we know anything about these genes is because the worm has them," Waterston said.
A series of reports in the journal Science describe how C. elegans has three times the number of genes a yeast organism has and about a fifth of the total genes a person has. It is estimated that humans have anywhere between 60,000 and 100,000 genes, but it will be at least five years before the human genome is mapped.
Copyright© 1998 Reuters Limited.
